With the arrival of a ubiquitous information society, an information terminal is demanded to transfer information anytime, anywhere. For such a terminal, flexible, light-weight, and inexpensive electronic devices are required, but the conventional devices using inorganic semiconductor materials such as silicon does not sufficiently meet the requirement. Accordingly, in recent years, electronic devices using organic semiconductor materials as semiconductors are intensively studied for satisfying such requirements (see, for example, Chemical Reviews, 2007, 107, p. 1296-1323, and “Organic Field-Effect Transistors”, 2007, CRC Press, p. 159-228).
Organic semiconductor materials are used as a photoelectric conversion material thereby obtaining organic photoelectric conversion devices such as optical sensors (see, for example, JP-A-2003-234460, JP-A-2003-332551, and JP-A-2005-268609 (“JP-A” means unexamined published Japanese patent application)), or organic thin-film solar cells (see, for example, “Organic Photovoltaics” (published in 2005, Taylor & Francis), p. 49-104, and Chemical Reviews, 2007, 107, p. 1324-1338). These organic photoelectric conversion devices are easier to produce as compared to the devices using inorganic semiconductor materials such as silicon. Especially, when an organic semiconductor material capable of performing film production according to a wet process is used, it is possible to manufacture large-scale devices at a low cost under a low temperature. There is ever reported, for example, the organic photoelectric conversion device using a photoelectric conversion layer that is a wet-process formed blend film composed of P3HT (poly (3-hexylthiophene)) and PCBM ([6,6]-phenyl-C61-butyric acid methyl ester). However, the photoelectric conversion performance of the conventional organic photoelectric conversion device is inferior to that of a silicon photoelectric conversion device. Therefore, improvement in performance of the organic photoelectric conversion device is demanded. The most outstanding issue to improvement in performance is that especially a long wavelength range (near infrared range) has not been used in the current device using both P3HT and PCBM because of a narrow light absorption wavelength range of the materials that are used in the device. Resultantly, energy conversion efficiency is low for use of the solar cell, and sensitivity that is required for an optical sensor is not provided in the long wavelength range (near infrared range). For this reason, it is required to develop an organic photoelectric conversion material capable of absorbing light even in a longer wavelength range (near infrared range), and capable of providing photoelectric conversion performance (see, for example, “Organic Photovoltaics” (published in 2005, Taylor & Francis), p. 49-104, and Chemical Reviews, 2007, 107, p. 1324-1338).
As a material capable of absorbing light even in a near infrared range, croconium dyes are known (see, for example, JP-A-2001-117201, and Dyes and Pigments, 1988, 10, p. 13-22). However, there is no specific description in which the croconium dye is actually used in an organic photoelectric conversion device. Consequently, no photoelectric conversion performance is confirmed.